JP2007200920A - Solder bonding structure of inserted mounting component, manufacturing method therefor and optical module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and high-reliability solder bonding structure of an inserted mounting component, without causing deterioration of the electrical characteristics, and to provide a manufacturing method of the structure. <P>SOLUTION: The solder bonding structure of the inserted mounting component is provided with a wiring board 1 having an insulating substrate 2 where a through-hole 4 is formed, a conductor 3 formed on a surface of the substrate 2, and electrodes 41 and 42 formed by exposing a face of the conductor 3 at a periphery of the through-hole 4 and coating a remaining conductor 3 with an insulating film 5; and with the inserted mounting component 6 where a lead electrode 61 is inserted into the through-hole 4 of the wiring board 1, and the lead electrode 61 is bonded to faces of the electrodes 41 and 42 with solder 91 and 92. The area of a face of the electrode 41 on a side, into which the lead electrode 61 is inserted, is made smaller than that of the face of the electrode 42 opposite to the face of the electrode 41, into which the lead electrode is to be inserted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solder joint structure for an insertion mounted component to a wiring board and a method for manufacturing the same.

  When soldering an insertion mounted component to a wiring board, the through hole of the wiring board is usually provided on the surface (first surface) of the wiring board on the side where the insertion mounting component is inserted and the opposite surface (second surface). The size of the electrode land is the same. Therefore, the height from the wiring board of the solder which spreads along the lead electrode of the insertion mounted component inserted into the through hole is substantially the same between the first surface side and the second surface side.

  As a method of soldering the insertion mounting component to the wiring board, the lead of the insertion mounting component is inserted into the through hole in which the electrode of the wiring board is formed, and then immersed in a solder bath containing molten solder, or the insertion mounting In general, a method has been used in which a solder wire is pressed against a lead of a component and then the wire solder is pressed and melted. However, as the density of mounted components increases and the distance between the lead electrodes of the inserted mounted components becomes smaller, the method of immersing in the solder bath causes the surface tension of the solder to act when it is pulled up from the solder bath, causing a short circuit between adjacent electrodes. In addition, in the method in which the thread solder is heated and melted with a soldering iron, solder is supplied and joined at the same time. there were.

  Therefore, a technique using a solder paste to solve the above-described problem and stably supply solder to electrodes with fine intervals has been disclosed (for example, see Patent Document 1).

  That is, after supplying the solder paste to the through-hole electrode of the wiring board by printing, after placing the block-shaped jig on the second surface opposite to the first surface of the wiring board, In this method, a lead electrode is inserted to melt the solder. This block-shaped jig has a shape devised so as not to cause a problem of insufficient solder by extruding the solder paste supplied in advance with the lead electrode of the insertion mounting component when inserting the insertion mounting component. .

JP 2004-140218 A (Page 5-8, FIGS. 1 to 6)

  When the size of the first surface and the second surface of the electrode of the through hole is the same, the height of the solder that has spread along the lead electrode of the insertion mounted component is the first surface side and the second surface side. And the gap between the insertion mounting component and the wiring board becomes large, and there is a problem that the electrical characteristics deteriorate due to an increase in inductance.

  Further, as in the soldering method disclosed in Patent Document 1, the method of combining the solder paste and the jig is different depending on the shape of the lead electrode of the insertion mounting component, the electrode interval, the number of electrodes, etc. There is a problem that the cost increases because it is necessary to prepare a jig.

  Further, since the entire lead electrode is covered with solder, the solder is cut when the lead pin is cut after joining, and there is a problem that cracks are generated in the solder at the time of cutting and the joining reliability is lowered due to the occurrence of cracks.

  Further, in order to press the inserted mounting component from the side to which the solder paste is supplied, there is a problem that when the pressing is performed, the paste is crushed and spreads, and is integrated with the solder paste of the adjacent electrode and short-circuited.

  The present invention has been made in order to solve the above-described problems, and provides a solder joint structure for a highly reliable insertion mounted component and a manufacturing method thereof at a low cost without deteriorating electrical characteristics. Objective.

The solder joint structure for an insertion mounting component according to the present invention remains with an insulating base material having a through hole formed thereon, a conductor formed on the surface of the base material, and a conductor surface surrounding the through hole exposed. A wiring board having an electrode formed by coating a conductor portion with an insulating film;
In a solder joint structure of an insertion mounting component having a lead electrode inserted into a through hole of the wiring board and an insertion mounting component in which the lead electrode is joined to the surface of the electrode by soldering,
The area of the electrode surface on the side where the lead electrode is inserted is made smaller than the area of the electrode surface on the side opposite to the electrode surface where the lead electrode is inserted.

The method for manufacturing a solder joint structure for an insertion mounting component according to the present invention includes an insulating base material in which a through hole is formed, a conductor formed on the surface of the base material, and a surface of the conductor around the through hole. A wiring board provided with an electrode formed by coating the remaining conductor part with an insulating film;
In a manufacturing method of a solder joint structure of an insertion mounting component having a lead electrode inserted into a through hole of the wiring board and an insertion mounting component in which the lead electrode is bonded to the surface of the electrode by solder,
Producing a wiring board in which the area of the electrode surface on the side where the lead electrode is inserted is smaller than the area of the electrode surface on the side opposite to the electrode surface on the side where the lead electrode is inserted;
A step of inserting the lead electrode of the inserted mounting component into the through hole of the produced wiring board,
Placing solder on the electrode surface exposed on the side opposite to the lead electrode insertion side;
Heating the lead electrode and solder to melt the solder;
It is what has.

An optical module according to the present invention includes an insulating base material in which a through hole is formed, an insulating base material in which a through hole is formed, a conductor formed on the surface of the base material, and a conductor around the through hole. A wiring board provided with an electrode formed by covering the remaining conductor portion with an insulating film, exposing the surface of
In an optical module having a light emitting element in which a lead electrode is inserted into a through hole of the wiring board and the lead electrode is joined to a surface of the electrode by solder and an insertion mounting component including a light receiving element.
The area of the electrode surface on the side where the lead electrode is inserted is made smaller than the area of the electrode surface on the side opposite to the electrode surface where the lead electrode is inserted.

  According to the solder joint structure of the insertion mounting component and the manufacturing method thereof and the optical module according to the present invention, the distance between the insertion mounting component and the wiring board is reduced, the inductance is reduced, the electrical characteristics are improved, and the lead electrode Since the solder wetting and spreading along the lead electrode on the opposite side of the insertion side is increased, the height to the tip of the solder is increased, sufficient bonding strength is obtained, and no special jig is required. Cost can be reduced.

  Further, according to the method for manufacturing a solder joint structure for an insertion mounted component according to the present invention, a plurality of lead electrodes can be joined with a predetermined amount of solder, and joint reliability can be improved.

Embodiment 1 FIG.
FIG. 1 is a cross-sectional view showing a first embodiment of a solder joint structure for an insertion mounted component according to the present invention. As shown in the figure, the wiring board 1 includes an insulating base 2, a through hole 4 provided in the base 2, an inner surface of the through hole 4, a conductor 3 made of copper or the like formed on the surface of the base 2, and a through hole 4 and the insulating film 5 covering the remaining conductor 3 portion by exposing the first electrode 41 on the insertion mounting component 6 side and the second electrode 42 on the opposite side to the insertion mounting component 6 of the through hole 4. Yes. The lead electrode 61 of the insertion mounting component 6 is inserted into the through hole 4 from the first electrode 41 side, and is joined to the wiring board 1 by the solder 91 on the first electrode 41 and the solder 92 on the second electrode 42. ing.

  The area of the first electrode 41 is smaller than the area of the second electrode 42, and the solder 91 on the first electrode 41 is soldered along the lead electrode 61 rather than the solder 92 on the second electrode. Therefore, the gap between the insertion component 6 and the wiring board 1 is reduced, the inductance is reduced, and the electrical characteristics are improved. Further, since the height from the second electrode 42 to the tip of the solder 92 is increased, a sufficient bonding strength can be obtained.

  As the wiring board 1 in the first embodiment, a conductor 3 is formed on both sides of a base material 2 made of a polyimide film having a thickness of 25 μm, and a polyimide cover film is pasted on the conductor 3, Without being limited thereto, an insulating film such as a liquid crystal polymer may be used as the base material 2, or a rigid substrate such as a glass epoxy substrate may be used.

FIG. 2 is a perspective view in which the insertion mounting component 6 and the lead electrode 61 of the wiring board 1 are soldered. In FIG. 2, there are a plurality of lead electrodes 61. The joining structure of each lead electrode 61 includes the joining structure of the first embodiment.
FIG. 2 shows an optical module in which a package of light emitting elements and light receiving elements (insertion mounting parts) is used as the insertion mounting component 6 and each lead electrode 61 is soldered to the flexible wiring board 1.

  FIG. 3 is a cross-sectional view showing another example in the first embodiment. As shown in FIG. 3, the conductor 3 of the wiring board 1 is provided on one side of the substrate 2, and the area of the exposed surface of the conductor 3 on the insertion side of the lead electrode 61 is defined as the conductor on the side opposite to the insertion side of the lead electrode 61. 3 is smaller than the area of the exposed surface.

  Since the area of the exposed surface of the conductor 3 on the insertion side of the lead electrode 61 is smaller than the area of the exposed surface of the conductor 3 on the side opposite to the insertion side of the lead electrode 61, the insertion mounting component 6 and the wiring board 1 The gap between them is reduced, inductance is reduced, and electrical characteristics are improved. Further, since the solder wetting and spreading along the lead electrode 61 is large on the side opposite to the insertion side of the lead electrode 61, the height to the tip of the solder 92 is increased, and sufficient bonding strength is obtained.

Embodiment 2. FIG.
FIG. 4 is a cross-sectional view illustrating the method for manufacturing the solder joint structure according to the first embodiment of the present invention.
First, as shown in FIG. 4A, the wiring board 1 having the through hole 4 and the first and second electrodes 41 and 42 is prepared. The base material 2 is composed of a material made of an organic material. For example, the base material 2 is made of glass epoxy obtained by hardening glass fibers with an epoxy resin in addition to a film such as polyimide or liquid crystal polymer, and aramid fiber is hardened with an epoxy resin. Use things. The through hole 4 is formed by drilling the base material 2 with a drill or a laser beam. The first and second electrodes 41 and 42 are formed by copper plating after the through hole 4 is formed.

  Next, as shown in FIG. 4B, the lead electrode 61 of the insertion mounted component 6 is passed through the through hole 4 and on the second electrode 42 of the through hole 4 as shown in FIG. In order to supply the solder 7 and to melt the solder 7, the heating tool 8 is pressed against the second electrode 42 and the lead electrode 61. The solder 7 uses solder balls or solder pellets to supply a certain amount. As the solder 7, a solder having a melting point of 240 ° C. or lower such as Sn-based SnAg, SnAgCu, or SnBi is used.

  4D, the heating tool is removed, the solder 7 is melted and then solidified, and the insertion mounted product 6 is joined to the wiring board 1. As shown in FIG.

  According to the second embodiment, the solder 7 is melted after the lead electrode 61 is inserted, so that a plurality of lead electrodes can be obtained as compared with the conventional method of supplying solder before the lead electrode 61 is inserted. 61 can be joined with a predetermined amount of solder 7, and the joining reliability can be improved.

Embodiment 3 FIG.
FIG. 5 is a cross-sectional view showing another method for manufacturing the solder joint structure of Embodiment 1 of the present invention.
As shown in FIG. 5, in the third embodiment, a solder paste 71 is used. The solder paste 71 is a paste in which solder particles having a diameter of several tens of μm are formed into a paste with a flux.

  The flux of the solder paste 71 has adhesiveness. Therefore, the solder paste 71 can be easily fixed on the second electrode 42.

  Further, since the solder paste 71 is in a paste form, a predetermined amount can be easily supplied using a dispenser, and the supply amount can be easily changed. Therefore, the solder paste 71 can be applied even when the second electrode 42 is narrow.

  INDUSTRIAL APPLICABILITY The present invention can be effectively used as a method for manufacturing a solder joint structure in which insertion mounting components such as a light emitting element and a light receiving element are joined to a wiring board.

It is sectional drawing which shows Embodiment 1 of the solder joint structure of the insertion mounting component which concerns on this invention. The perspective view which soldered the insertion mounting component 6 and the lead electrode 61 of the wiring board 1 is shown. 6 is a cross-sectional view showing another example in the first embodiment. FIG. It is sectional drawing which shows the manufacturing method of the solder joint structure of Embodiment 1 of this invention. It is sectional drawing which shows the other manufacturing method of the solder joint structure of Embodiment 1 of this invention.

Explanation of symbols

1 Wiring board 2 Base material 3 Conductor 4 Through hole 5 Insulating film
6 Insert mounting parts, 7 Solder, 8 Heating tool, 9 Solder solidified by melting,
41 1st electrode, 42 2nd electrode, 61 lead electrode, 71 solder paste,
91 Solder on the first electrode, 92 Solder on the second electrode.

Claims (5)

Insulating base material in which through holes are formed, a conductor formed on the surface of the base material, and an electrode formed by covering a conductor portion exposed by exposing the surface of the conductor around the through hole with an insulating film A wiring board comprising:
In a solder joint structure of an insertion mounting component having a lead electrode inserted into a through hole of the wiring board and an insertion mounting component in which the lead electrode is joined to the surface of the electrode by soldering,
A solder joint structure for insertion mounting parts, wherein the area of the electrode surface on the side where the lead electrode is inserted is smaller than the area of the electrode surface on the side opposite to the electrode surface where the lead electrode is inserted. 2. The solder joint structure for insertion mounting parts according to claim 1, wherein the conductor is formed on one side of the substrate. Insulating base material in which through holes are formed, a conductor formed on the surface of the base material, and an electrode formed by covering a conductor portion exposed by exposing the surface of the conductor around the through hole with an insulating film A wiring board comprising:
In a manufacturing method of a solder joint structure of an insertion mounting component having a lead electrode inserted into a through hole of the wiring board and an insertion mounting component in which the lead electrode is bonded to the surface of the electrode by solder,
Producing a wiring board in which the area of the electrode surface on the side where the lead electrode is inserted is smaller than the area of the electrode surface on the side opposite to the electrode surface on the side where the lead electrode is inserted;
A step of inserting the lead electrode of the inserted mounting component into the through hole of the produced wiring board,
Placing solder on the electrode surface exposed on the side opposite to the lead electrode insertion side;
Heating the lead electrode and solder to melt the solder;
A method of manufacturing a solder joint structure for an insertion-mounted component, comprising: 4. The method for manufacturing a solder joint structure for an insertion mounted component according to claim 3, wherein the solder is a solder paste. Insulating base material in which through holes are formed, a conductor formed on the surface of the base material, and an electrode formed by covering a conductor portion exposed by exposing the surface of the conductor around the through hole with an insulating film A wiring board comprising:
In an optical module having a light emitting element in which a lead electrode is inserted into a through hole of the wiring board and the lead electrode is joined to a surface of the electrode by solder and an insertion mounting component including a light receiving element.
An optical module characterized in that the area of the electrode surface on the side where the lead electrode is inserted is made smaller than the area of the electrode surface on the side opposite to the electrode surface where the lead electrode is inserted.

Images